[Coral-List] Coral immortality
atolldino at yahoo.com
Thu Mar 31 20:13:50 EDT 2011
The notion of coral colonies being chimeral mosaics, not genetically identical, began to interest me during the 2009 Majuro atoll bleaching episode (during which Porites mortality occurred in the lagoon, possibly for the first time). I have images of specific Porites cf lutea colonies before, during and after bleaching. Seemingly identical colonies (apart from beautiful variations in color) exhibited a wide variety of bleaching patterns: unbleached, fully bleached, bleached on top (crown) and bleached only on the sides, as well as lots of mottled bleaching. They were all growing at the same depth and location (barely subtidal) so experienced nearly identical light and temperature.
Following recovery, in January, I saw that the pattern of tissue loss (bleaching mortality) could be striking: on one particular colony, mottled tissue loss was found up to the boundaries of two shallow hemispherical swellings (not really growth anomalies, they had normal texture, the swellings just seemed to be clonal regions of faster growth). There was no tissue loss at all on the "swelling", which had both partially bleached.
Patches of tissue loss persist with time, and are records of the most severe of past bleaching events.
Besides genetic differences, it has been said before that differences in symbiont and mucus bacterial genotypes may also be important.
College of the Marshall Islands
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